Kadyrov, whose term as leader runs out next month, was appointed acting leader by Putin and is expected to stand in elections in September. He had previously said he planned to step down, but most analysts saw this as a ploy to force the Kremlin to back him publicly, after a year in which he has faced criticism from many quarters.

In return for the loyalty Kadyrov has pledged to Moscow, critics say he has been allowed a free hand to run the republic. Russian law often appears to be secondary to local customs or Kadyrov's personal whims, and many of those who have investigated abuses by Kadyrov's forces have met sticky ends.

A high-ranking member of one of the armed battalions under Kadyrov's control was charged with Nemtsov's murder in Moscow last year. The politician was shot in the shadow of the Kremlin, a murder which shocked Russia, and there are suspicions that the chain of command goes much higher than the men who have been arrested. However, investigators have been unable to question Kadyrov or his associates over the killing.

While many in the higher echelons of Russian power dislike Kadyrov, he has always retained the support of Putin. The Russian president said on Friday he had reappointed Kadyrov because of "everything that has been done in the past years for the Chechen people first and foremost, and by extension for the whole of Russia".

"There needs to be more attention paid to the federal power structures. You, and future leaders of your republic should of course do everything to ensure that Russian laws are obeyed in all spheres of life. I want to emphasise this: in all spheres of life,"Putin said.